Freestanding wall structures made using sandbags

ABSTRACT

A freestanding wall structure comprises a pair of opposed wall faces formed of sandbags with a mass of fill therebetween. The sandbags are attached together by means of interconnecting members. Sheets of geogrid extend between the two wall faces through the fill, attached to the interconnecting members, and support the wall faces and hold the wall structure together.

TECHNICAL FIELD

The invention pertains to walls and methods of constructing walls using sandbags.

BACKGROUND OF THE INVENTION

Walls are used in a variety of civil engineering, erosion control, environmental and landscaping applications, for example to demark and divide areas of ground, to provide noise barriers, etc. Typically, such walls are relatively expensive structures made of blocks, bricks, plates, wooden planks, etc., fastened together. Conventionally, freestanding walls have not been made of sandbags due to the inability to make a stable and relatively high and narrow wall using such materials. International Patent Publication No. WO 00/61880 (Kim) published Oct. 19, 2000 discloses a system of building retaining walls from sandbags which uses interconnecting members to attach the sandbags in adjacent courses to each other in order to stabilize and strengthen the sandbag retaining wall structure, permitting the construction of permanent retaining wall structures. The interconnecting members are plates having projections on both sides that protrude into horizontally and vertically adjacent sandbags. Such retaining walls form the face of a slope or embankment and are not freestanding walls. It would be desirable to be able to construct stable freestanding walls using sandbags that are interconnected together.

SUMMARY OF THE INVENTION

The invention provides a wall structure having two opposed wall faces constructed of sandbags connected together by means of interconnecting members, a mass of fill between the two wall faces and holding means, such as sheets of geogrid, that extend between the two wall faces, through the mass of fill, holding the wall structure together.

The wall structure according to the invention comprises a plurality of courses forming a first wall face, each course comprising a plurality of sandbags, and a second plurality of courses of sandbags forming a second wall face. Interconnecting members are positioned between vertically adjacent courses of each wall face to connect the sandbags in each course to the adjacent courses. The interconnecting members have attachment means to attach to wall-holding means. There is a mass of fill between the two wall faces, supported by the wall faces. The wall-holding means extends between the two wall faces through the fill, attached to the interconnecting members. The wall-holding means connects the two wall faces together and resists the outwardly-directed forces on the wall faces. The wall-holding means preferably comprises one or more sheets of geogrid. Other wall-holding means includes sheets of geotextile or other material, cables or rods made of metal or other suitable materials, wooden members, ropes, etc.

The invention also provides a method of constructing a wall structure as aforesaid. A plurality of sandbags is placed to form a course of the first wall face and another plurality of sandbags is placed to form a course of the second wall face. Interconnecting members are placed on the courses and a mass of fill is placed in the space between the two courses. Wall-holding means are then attached to the interconnecting members on both courses, extending between them and over the mass of fill between the courses. The steps are repeated one or more times to build additional courses to extend the height of the wall structure as required.

The wall structures of the invention have the advantage of being less expensive to build than those made using conventional materials. They can also be adapted for the growth of vegetation on the wall faces.

In this specification, “fill material” means any material that is suitable for use in bags in the construction of walls, including sand, soil, gravel, dry mix concrete (which hardens after wetting and curing) and mixtures thereof, including fill material with seeds for vegetation. The term “sandbag” as used herein means a bag containing any “fill material.” For further clarity, the term is not limited to a bag in which the fill material is sand.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical cross-sectional view through a wall made in accordance with the invention.

FIG. 2 is an enlarged cross-sectional view through the wall showing an interconnecting member in position between vertically adjacent courses.

FIG. 3 is a sectional view on the line 3-3 of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 to 3, a wall structure 10 according to the invention is constructed on ground 12 and has two opposed, spaced-apart wall faces 14, 16. Each wall face comprises a plurality of courses 18 of sandbags 15. The wall structure is preferably laid generally horizontally, though it may follow the contour of the ground as required.

The courses of each wall face are laid one above the other so as to create a wall face that is preferably sloped inwardly, making the wall narrower at the top than the bottom, to enhance the stability of the wall, though one or both faces may be substantially vertical if desired. The space between the two faces 14, 16 is filled with a compacted mass of fill 20, which may comprise soil, sand, gravel, rocks, etc. The sandbags of vertically adjacent courses are preferably positioned in a staggered arrangement, i.e. so that each sandbag in a course rests on two horizontally adjacent sandbags in the vertically adjacent lower course, as seen in FIG. 3.

The sandbags are preferably made of a geotextile material that is durable and permits water to flow into and through the bags, and seedlings to grow out, while retaining fine soil particles within the bag. The material of the bags should not be biodegradable, for durability of the wall. The sandbags may contain plant seeds so that a plant cover can be grown on the exterior of the wall faces.

Interconnecting members 22 are used in the construction of the retaining wall 10. Interconnecting member 22 comprises a plate 24, preferably rectangular and planar in shape, with a plurality of projections 26, 27 extending from the upper and the lower sides respectively of the plate. Projections 26, 27 are sufficiently strong and pointed to protrude into the sandbags. Interconnecting member 22 is preferably made of plastics or aluminum or other non-corrodible material. The upper side of the plate 24 has hooks 28 configured to attach the interconnecting member to a sheet of geogrid 30. Preferred dimensions of the interconnecting member are about 286 millimeters in length, 100 millimeters in width and 42 millimeters in height (including the projections). Generally, the interconnecting members may be of the types described in International Publication No. WO 00/61880 dated Oct. 19, 2000, adapted for attachment to a sheet of geogrid.

The interconnecting members 22 are used to anchor geogrid sheets, which, in the preferred embodiment of the invention is the wall-holding means, to the sandbags. Geogrid sheets 30 are commercially available plastic mesh products commonly used for soil reinforcement. Geogrid sheet 30 has a plurality of holes 32 therein. The sheet 30 is affixed to the faces of the wall by placing the edge of the sheet over interconnecting members 22 atop a course of sandbags 18 so that the hooks 28 on the upper side of the interconnecting member and adjacent to its back edge protrude through holes 32 in the geogrid sheet. When the next upper course 18 of sandbags is put on top, hooks 28, extending through the geogrid sheet, press against the underside of the bags in said upper course.

When a course of sandbags is placed on top of a lower course and on the interconnecting members 22 thereon, the projections 26 on the upper side of the plate protrude into the sandbags in the upper course, and the weight of such sandbags presses the interconnecting member so that the projections 27 on their lower side protrude fully into the sandbags in the lower course. The projections 26, 27 can be configured to fully penetrate the sandbags, or, preferably, to simply indent them. In either case, the projections are considered to “protrude” into the sandbags.

Interconnecting members 22 are of a size and configuration such that, when a member 22 is placed covering a portion of two abutting sandbags within a course, some of the projections 27 on the lower side of the plate will protrude into each of the two horizontally abutting sandbags, connecting them together, and when a sandbag is placed on top of such plate, i.e. in laying a vertically adjacent upper course, projections 26 on the upper side of the member will protrude into that sandbag, attaching the upper sandbag to the two lower sandbags. Thus, the interconnecting members attach both horizontally and vertically adjacent sandbags at the same time.

Geogrid sheets are installed at selected levels during the construction of the wall 10, for example on top of every course of bags, or every second or third course, as required to support both wall faces of a wall having a given length, height and width. The geogrid sheets 30, being attached to the wall faces 14, 16, resist outward pressure on the wall faces caused by the mass of fill between the faces, and hold the wall faces in a stable and fixed position, permitting the wall to be freestanding, supported only by the underlying ground.

In order to construct the sandbag wall structure of the invention, a plurality of sandbags is placed on the ground to form the bottom course of the first wall face 14, and a plurality of sandbags is placed on the ground to form the bottom course of the second wall face 16, the course of the second wall face being spaced from the course of the first wall face. Interconnecting members 22 are placed on both of these courses. Each interconnecting member is preferably placed so as to cover a portion of two horizontally adjacent sandbags, so that projections 27 on the lower side of the interconnecting members will protrude into both of said horizontally adjacent sandbags. Fill is placed and compacted into the space between the two courses of sandbags. This can be done either before or after the interconnecting members are placed on the courses. A sheet of geogrid is then attached to the interconnecting members on both courses, extending between the two courses. The wall is then built up to the desired height by repeating these steps to add further courses of sandbags and build the wall faces, and the wall structure, to the desired height. The geogrid sheets are used at selected levels, optionally but not necessarily at every course. A top course of sandbags is placed on top of the two wall faces to complete the structure.

If desired, the interconnecting members can be used in the inverted position, i.e. with a sheet of geogrid placed directly on the courses of sandbags and the interconnecting members placed on top of them with the hooks 28 facing downward and extending through the sheet of geogrid. It is, however, more convenient to use the interconnecting members in the orientation described above, with the sheet of geogrid on top of the interconnecting members.

While exemplary embodiments have been discussed above, those of skill in the art will recognize that certain modifications thereof may be made. For example, any of numerous means may be used as the wall-holding means. The attachment means on the interconnecting members may be of any suitable form in order to attach to a particular wall-holding means. Even where the wall-holding means is geogrid, attachment means other than hooks, such as simple projections, can be used to attach the geogrid to the interconnecting members. Further, the interconnecting members can be of any shape and configuration that are suitable for connecting sandbags in a particular application. It is therefore intended that the following appended claims are interpreted to include all such modifications, as are within their true scope. 

1. A wall structure comprising: (a) a plurality of courses of sandbags forming a first wall face, each said course comprising a plurality of sandbags; (b) a second plurality of courses of sandbags forming a second wall face, each said course comprising a plurality of sandbags; (c) interconnecting members positioned between adjacent courses of each wall face to connect said sandbags of said courses to sandbags of an adjacent said course, said interconnecting members having means to attach to a wall-holding means; (d) a mass of fill between said two wall faces and supported thereby; and (e) said wall-holding means extending between said first wall face and said second wall face through said fill material and attached to said interconnecting members.
 2. A wall structure according to claim 1 wherein said wall-holding means comprises a sheet of geogrid.
 3. A wall structure according to claim 1 wherein said wall-holding means is one of a sheet of geotextile, a cable, a rod, a wooden member and a rope.
 4. A wall structure according to claim 1 wherein said interconnecting member is a plate having an upper side and a lower side, each said side having a plurality of projections thereon, said plate being capable of extending across at least part of two adjacent sandbags in one said course with said projections on said upper side or said lower side protruding into said two adjacent sandbags.
 5. A wall structure according to claim 1 wherein said opposed wall faces slope towards each other in the upward direction.
 6. A wall structure according to claim 1 wherein said sandbags are made of geotextile.
 7. A wall structure according to claim 1 further comprising plants on the exterior of one or both of said wall faces growing from said sandbags.
 8. A method of constructing a wall structure having first and second opposed wall faces and a mass of fill therebetween, comprising the steps of: (a) placing a plurality of sandbags to form a course of said first wall face; (b) placing a plurality of sandbags to form a course of said second wall face, said course of said second wall face being spaced from said course of said first wall face; (c) placing interconnecting members on both said courses, said interconnecting members being adapted to connect adjacent sandbags together and having means to attach to a wall-holding means; (d) placing said fill in the space between said courses of sandbags; (e) attaching said wall-holding means to said interconnecting members on both said courses so that said sheet extends between said courses; and (f) repeating steps (a) to (e) one or more times to build one or more additional courses extending the height of said wall structure.
 9. A method according to claim 8 wherein said wall-holding means comprises a sheet of geogrid.
 10. A method according to claim 8 wherein said wall-holding means is one of a sheet of geotextile, a cable, a rod, a wooden member and a rope. 